Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to DC Volts 
CH Demand
Gain access to terminal block, located underneath boiler
Use insulation mat as required
Use insulation mat as required
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Measure for DC voltage across pin 2 (brown wire) of terminal block to a suitable earth connection.
Expected voltage approximately 24V DC.
Expected voltage approximately 24V DC.
Isolate as per TOPs P4
and refit as necessary